


Desire // Yandere!Reader x Underfell!Sans

by lovesnapped



Series: Reader X Undertale Characters -- Yandere Edition! [1]
Category: Underfell - Fandom, Undertale
Genre: ;), Alternate Universe, Alternate Universe (Underfell), Alternate Universe - Underfell, Gore, Horror, Multi, Mutilation, Other, Reader Insert, Skeletons, Underfell, Underfell AU, Undertale AU, Undertale Alternate Universe, Yandere, Yandere Reader
Language: English
Status: Completed
Published: 2018-04-06
Updated: 2018-04-11
Packaged: 2019-04-19 10:08:59
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings, Graphic Depictions Of Violence, Major Character Death
Chapters: 3
Words: 1,369
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14234976
Author URL: https://archiveofourown.org/users/lovesnapped/pseuds/lovesnapped
Summary: Yanderu is a Japanese word that means 'mentally sick illness', the Japanese word, 'Deredere' means 'showing strong affection'.Combining these words into a single word: Yandere. A strong, mentally sick affection.There are no words in the English vocabulary that would truly describe what this word means, but it is correlated with a character that has so much attachment to a single person that they stalk their crush and kill any person that becomes an obstacle.❤♡❣ ~ ❣♡❤





	1. Chapter 1

Scratching the back of his skull, he looked uneasy. He nervously shuffled with his fuzzy hoodie, tousling the fur and trying to fix the unkempt fleece to pass the time. Sans barely glanced at the news reporter droning on in the TV screen. He felt...antsy again.

His brother had been missing for a couple of days only after a handful of months passed on the surface. Now, his brother had said that he would attempt to hang out with others--human or not to try to get at least himself a good reputation.

Personally, his brother is a complete softie and he knows that, he knows Papyrus just likes to act tougher than he actually is when people are watching. It is normal, if anything, it is a life-saver. They would both be dead as soon as they grew up in the underground if his brother was not intimidating.

Sans may have expected his brother to come home a tad bit late, but he simply did not expect him to be this late. Papyrus is normally punctual. He still is not home, either. Sans would not really admit this to anyone that he knows, but he does miss his brother. Big guy is probably having fun, huh?

He does not really feel so safe. Adding onto the fact that his brother is missing, he feels like things have shifted in rooms from where he last left them. His belongings are normally moved to different places that he does not even remember moving them to. Ordinarily, he would have suspected that Papyrus moved his possessions, but Papyrus has not been home for nearly a week.

There is a feeling of being watched for him especially when he was home, too. Cold fingers dance up his spine whenever he has the feeling of being watched, making him bristle and attempt to look for the source. 

You found this adorable, the way his shoulders would raise and how quickly his calm and relaxed expression turned terrified just made him all more cute. Generally, you did not have any kind of intense feelings for anybody of the sort, unlike this oddball of a skeleton did. You know that you could flatter anybody that you pleased, but somehow the thought of attempting to flatter him first slips your mind.

The most that you would want is him. All to yourself, with nobody else becoming a hindrance to getting him. That would mean his brother--His beloved brother would have to be rid of, as he is a troubling (and quite annoying) inconvenience that you barely have any time to deal with.

The more you noticed him glancing at the calendar, would be the more you noticed looking at pictures of his brother. It would go to noticing how much he glances at his phone to see a new text from his brother, how much he skims through old conversations with his brother and tries to call him but his brother never picks up.

 

Waking up in haze, he tiredly looked down at the clock of his almost drained phone, to find a new message from his brother's number--an image and a few more words. Every thought of doubt or worry snapped from him and he was apace to check what his brother sent.

However, that moment lasted quickly, as his heart-or SOUL-or what is left of it dropped to his feet, a sinking feeling in his chest that almost stopped him from breathing erupted. A picture of his brother, tied up and beaten, yet still alive due to the fact that he has not dusted yet. 

Message sent an hour ago, the message read "You have one hour to go to this address and save him."


	2. Chapter 2

Breaking bones in this messy and witless way caused them to splinter into pointed shards. You've heard at least a few of the names of some types of broken bones in your life--the patterns on how bones get fractured and break. 

The broken bones exactly weren't the prettiest sight, but you've heard of some sort of myth about a certain species of monsters that hid away to die during the war carved their life stories into the bones of humans they have killed. It was something you wanted to study for a long time, but you could barely find any books about it. Either anything written about it was discarded, or maybe the species of monster was rare? Maybe that species died out and everyone else found the leftovers of what they had?...or it was just a petty human rumor.

You ran your fingertips over the cracks on the tall skeleton's face. He had probably fainted out of pain. The sort of scars over his eye seemed to be some sort of greenstick fracture, though didn't they only happen in children? You weren't that much of a doctor, but you assumed he may have had that wound as a child and grew up with it.

Curling your nail under the tiny fragments of bone that stuck out, you leisurely ripped them off. You were sluggishly marring and disfiguring his face by snapping off the wound, prolonging your wait time. Eventually you had snapped off a bone deep enough and what you could assume was bone marrow fluid mixed with blood slipped down his skull and onto your hand.

You heard a door upstairs slam open, and you jolted upwards, scratching off a good bit off his skull. Moving to press the lingering skeleton's body against the corner of the basement, you pulled on your mask and inaudibly stepped upstairs as he recklessly wandered throughout your home.

It wasn't expected for Sans to take so long to get here. You thought he at least cared for that shitstain for a brother. You nearly bet ten minutes tops, but instead, it was past the hour it was due. You should have killed his brother.


	3. Chapter 3

**Summary for the Chapter:**

> Give recommendations if you please!

Your front door was blown off of its hinges, a circular hole ripping straight through the aged wood. Chunks of burnt wood was just a few inches away from the door, as if some sort of giant flaming bullet shot right through. 

The skeleton was more than likely rampaging throughout your home. You could hear a glass breaking from upstairs and a sharp yell. You didn't really know if he fell for a booby trap of yours or he just stepped on glass that he broke himself.

Sighing, you adjusted your mask. You were already breathing hard at the thought of being with him, at the thought of wrapping him up nice and good just for yourself. Your face was sweating and your hands were a tad clammy.

Prowling up the stairs, you budged to peek onto the skeleton in the hallway. Of course, that imbecile just had to let a glass vase fall on himself, the dirt and water in the vase now all over him, and the flower that was previously contained was now crushed on the floor under one of his shoes.

He growled, trying to wipe the filth off of his face. In the process, he stumbled over his own feet on a larger shard, making him fall onto the floor. Why do you love this dumbass of a skeleton? Then again, he'd be your dumbass.

You pulled him up by his dripping hoodie, the fur on it uncomfortably warm and sopping. He let out a shriek once he stared you in the eye (or, at least of what he could make of with a mask on). Once he struggled, you dropped him to the ground so he could fall on the sharp glass. 

He thrashed and hurried to get up, wincing and yelping in the process. "You!" He delievered a weak punch, glass was sunk through his coat and into his arms. He was bleeding.

Not saying anything quite yet, you just tugged him by the hoodie. His skull crashed against the corner of the table that previously held the vase. Once he could barely even look you in the eye from the blood dripping from his forehead and into his eyesockets, you strolled along to the basement, your bleeding skeleton being dragged not far behind you.


End file.
